Compound Bipolar Ablation Device and Method

ABSTRACT

Method and apparatus for ablating target tissue adjacent pulmonary veins of a patient. The ablation device can include a lower jaw assembly including a proximal jaw having a proximal electrode and a distal jaw having a distal electrode, and an upper jaw assembly including an upper jaw having an upper electrode. A proximal actuator can be movable between a first position in which the proximal jaw is open and a second position in which the proximal jaw is clamped with respect to the upper jaw. A distal actuator can be movable between a third position in which the distal jaw is open and a fourth position in which the distal jaw is clamped with respect to the upper jaw.

RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 60/576,245 filed on Jun. 2, 2004, which is incorporated herein by reference in its entirety.

BACKGROUND

Various types of electrocautery devices are used for ablating tissue. Typically, such devices include a conductive tip or blade which serves as one electrode in an electrical circuit which is completed via a grounding electrode coupled to the patient. With sufficiently high levels of electrical energy between the two electrodes, heat is generated which is sufficient to denature proteins within the tissue and cause cell death.

By controlling the energy level, the amount of heat generated and the degree, of tissue damage can also be controlled. High levels of voltage can actually cut and remove tissue (i.e., electrosurgery), while lower levels will simply create sufficient heat to cause cell damage, but leave the structure intact (i.e., catheter ablation) and block electrical pathways within the tissue. Irrigation of the electrode(s) with saline or other conductive fluid can decrease the interface impedance, cool the tissue and allow for a greater lesion depth.

The treatment of chronic atrial fibrillation (AF) requires the creation of numerous linear lesions that extend completely through the thickness of the tissue. Some electrophysiologists have created these lesions using a tip electrode of standard ablation catheters. These catheters were designed to create spot lesions, typically for ablation of specific structures or focal abnormalities. In order to make the linear lesions required to replicate the MAZE procedure, an electrophysiologist makes a series of focal lesions, and “connects the dots.”

Manufacturers have therefore developed catheters that have a linear array of electrodes along a long axis (i.e., the Amazr, MECCA, and Revelation catheters). The catheter and electrodes can be positioned in contact with the tissue and either individually or sequentially apply energy to each electrode. Additionally, catheters which incorporate an electrode which is energized and moves along the length have been proposed.

Surgeons have also been able to create linear lesions on the heart using applications of the same techniques. For example, Kottkamp et al. in an article entitled “Intraoperative Radiofrequency Ablation of Chronic Atrial Fibrillation: A Left Atrial Curative Approach by Elimination of Anatomic ‘Anchor’ Reentrant Circuits,” Journal of Cardiovascular Electrophysiology, 1999; §10:772-780 disclosed using a hand-held device that creates as series of spot or short (<1 cm) linear lesions. Other investigators have used long, linear unipolar probes to create somewhat longer lesions, such as described by Shirmoikd E. et al. in an article entitled “In Vivo and In Vitro Study of Radio-Frequency Application with a New Long Linear Probe: Implication for the MAZE Procedure,” Journal of Thoracic and Cardiovascular Surgery, 2000; §120:164-72. Still others have used multi-electrode linear catheters, similar to those described above to create a series of ablations that net a linear lesion, as described by Melo J. et al. in an article entitled “Endocardial and Epicardial Radiofrequency Ablation in the Treatment of Atrial Fibrillation with a New Intra-Operative Device,” European Journal of Cardio-Thoracic Surgery; 2000; §18:182-186.

U.S. patent application Ser. No. 10/015,690, in the names of Francisichelli et al. describes a bipolar ablation device that integrates an electrode into jaws of a hemostat-like or forceps-like device, known as the Cardioblate-BP. This results in a tool that can clamp and ablate the tissue in between the jaws. In conjunction with a transmurality algorithm, this configuration is amenable to creating transmural lesions. However, the Cardioblate-BP was designed to access the heart via a mid-line sternotomy. In order for the therapy to be considered as stand-alone, access must be made less invasively. Simply placing the Cardioblate-BP jaw onto an endoscopic handle has certain advantages, but there are significant limitations when trying to manipulate both jaws simultaneously through separate tissue spaces.

A microwave device that can loop around the posterior of the heart to encircle the pulmonary veins has been developed. A right thorocotomy is created at about the fourth intercostal space, and the pericardium is freed behind the superior vena cava and the inferior vena cava. A moveable antenna slides within an integral sheath and discrete sections are ablated in series is described by Saltman, “AE in a Completely Endoscopic Approach to Microwave Ablation for Atrial Fibrillation,” Heart Surgery Forum, 2003, 6(3):E38-E41.

Today, the MAZE procedure is performed with traditional cut and sew techniques. The market is demanding quicker, safer and less invasive approaches. Many companies are developing ablation techniques that heat (or cool) and thermally destroy the underlying tissue. Methods of chemical ablation have also been proposed.

SUMMARY OF THE INVENTION

Accordingly, there is a need for a method and device that results in less trauma to the patient, fewer insertions and removals of the ablation tools, and more flexibility for selecting ablation configurations using a single tool to ablate target tissue of a patient's heart. A need also exists for a compound bipolar ablation device for minimally-invasive isolation of the pulmonary veins without completely occlude blood flow.

Some embodiments of the invention provide an ablation device for ablating target tissue adjacent pulmonary veins of a patient. The ablation device can include a lower jaw assembly including a proximal jaw having a proximal electrode and a distal jaw having a distal electrode, and an upper jaw assembly including an upper jaw having an upper electrode. A proximal actuator can be movable between a first position in which the proximal jaw is open and a second position in which the proximal jaw is clamped with respect to the upper jaw. A distal actuator can be movable between a third position in which the distal jaw is open and a fourth position in which the distal jaw is clamped with respect to the upper jaw.

Embodiments of a method of the invention can include inserting a lower jaw assembly through an incision in the patient and inserting an upper jaw assembly through the incision. The method can include coupling the upper jaw assembly to the lower jaw assembly. The method can also include moving at least one of a proximal actuator and a distal actuator in order to position at least one of a proximal jaw and a distal jaw with respect to an upper jaw and providing ablation energy to at least one of an upper electrode, a proximal electrode, and a distal electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a posterior cross-sectional view of a patient's heart and a conventional bipolar ablation device.

FIG. 2 is a posterior cross-sectional view of a patient's heart and a schematic representation of a compound bipolar ablation device according to one embodiment of the invention.

FIGS. 3, 3A, and 3B are perspective and cross-sectional views, of a lower jaw assembly of a compound bipolar ablation device according to one embodiment of the invention.

FIGS. 4 and 4A are perspective and cross-sectional views of a compound bipolar ablation device according to one embodiment of the invention, including the lower jaw assembly of FIG. 3 and an upper jaw assembly.

FIG. 5 is a perspective view of the compound bipolar ablation device of FIG. 4 having a cable clamp in a locking position.

FIG. 6 is a perspective view of the compound bipolar ablation device of FIGS. 4 and 5, including a distal jaw engaged with an upper electrode.

FIG. 7 is a perspective view of the compound bipolar ablation device of FIGS. 4 and 5, including the distal jaw and a proximal jaw engaged with the upper electrode.

FIG. 8 is a perspective view of the compound bipolar ablation device of FIGS. 4 and 5, including the proximal jaw engaged with the upper electrode.

FIG. 9 is a perspective view of a compound bipolar ablation device according to another embodiment of the invention.

FIGS. 10, 10A, and 10B are perspective views of a compound bipolar ablation device according to another embodiment of the invention.

FIG. 11 is a perspective view of a compound bipolar ablation device according to another embodiment of the invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limited. The use of “including,” “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “mounted,” “connected” and “coupled” are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect.

FIG. 1 is a posterior cross-sectional view of a patient's heart illustrating atrial tissue 10, pulmonary veins 12, right pulmonary veins 14, left pulmonary veins 16, and the oblique sinus 18. FIG. 1 also illustrates a conventional bipolar ablation device including a superior jaw 20 and an inferior jaw 22. When creating lesions with conventional bipolar clamping-type devices, both jaws 20, 22 (containing electrodes) are manipulated simultaneously through two separate tissue planes, as shown in FIG. 1. For example, if a surgeon wants to ablate around the pulmonary veins 12, one jaw 20 would have to be placed behind the superior vena cava, through the transverse sinus, and over the superior pulmonary veins. Simultaneously, the other jaw 22 would need to be placed behind the inferior vena cava, through the oblique sinus 18 and under the inferior pulmonary veins. This is further complicated by the relatively fixed angle at a hinge joint of the clamping device. As a result, a surgeon has difficulty in simultaneously advancing both jaws 20, 22 into two separate tissue spaces. Although the superior jaw 20 can be manipulated into the transverse sinus, the inferior jaw 22 is hindered from the oblique sinus 18 by the right inferior pulmonary vein 14.

FIG. 2 is a posterior cross-sectional view of a patient's heart and jaws 24, 26 placed independently into two separate spaces according to one embodiment of the invention. After positioning, both jaws 24, 26 can be joined at a hinge point. This is a less invasive approach, resulting in less trauma to the patient than during a sternotomy. Some embodiments of the invention provide a bipolar ablation device that can produce a narrower lesion than a monopolar. A bipolar ablation device according to some embodiments of the invention can create a long continuous lesion with two separate ablations, without completely occluding blood flow (resulting in less trauma than complete occlusion of the pulmonary veins 12).

Some embodiments of the invention provide an ablation device having separable compound jaws for clamping to apply energy, such as radio frequency energy, to ablate tissue in the heart of a patient suffering from atrial fibrillation. After appropriate dissection, the separable jaws can be placed in the thoracic cavity through an incision. This can be through a thorocotomy, sub-xyphoid incision, stemotomy, or other suitable incisions. Ports may be used to aid insertion, and a positioning device, such as a Starfish positioning device manufactured by Medtronic, Inc., may also be used to lift, rotate, or elevate the heart.

As shown schematically in FIG. 2, using a small incision in the patient's chest, an ablation device 30 can be inserted piecemeal into a position in the patient's chest. The pieces (e.g., jaws 24, 26) can be assembled and manipulated to bring electrodes into contact with a patient's beating heart. Selecting the appropriate configuration of the compound jaws 24, 26 to engage and ablate tissue in the heart, the surgeon can perform the ablation procedure quickly without removal, manipulation, or substitution and reinsertion of the ablation device 30. Some embodiments of the invention provide a clamping ablation device 30 with independent separable jaws 24, 26. Each jaw 24, 26 can be individually manipulated into the appropriate space. Once positioned, the jaws 24, 26 can be brought together to create a bipolar system.

Embodiments of the invention can results in a patient experiencing less trauma because of the minimal invasiveness of delivering the working bipolar ablators to the heart tissue to be treated. Blood contacting devices, such as catheters, may not be used so that the use of biomaterials may not be required.

Embodiments of the invention can allow the surgeon to make narrow, linear ablation lesions quickly to reduce the time the patient is in the procedure. The surgeon can create the lesions deeply in the tissue of the heart while minimizing the damage to surrounding tissue. The creation of a long lesion can be achieved by making contiguous lesions using the ablation device 30. The compound jaws 24, 26 can allow the surgeon to selectively make a lesion using a proximal electrode set, a distal electrode set, or both sets simultaneously, depending on the conditions.

Embodiments of the invention can be adapted to maneuver around tissue that should be protected and minimize removal and reinsertion of different types of ablation devices to quickly achieve the desired ablation of the patient's heart tissue. One embodiment of the invention can be a configurable configuration that can allow the ablation device 30 to be used as a bipolar clamp for creating ablative lesions in three different configurations without removal from the patient's chest.

In general, the bipolar ablation device 30 can minimize the invasive nature of the procedure of ablating tissue in the patient's heart. The method and apparatus of the invention can result in less trauma to the patient and less chance of accidentally damaging the heart and surrounding structures. Embodiments of the invention can minimize trauma to the patient by minimizing the size of the incision required to insert the ablation device 30 through the patient's chest wall. Embodiments of the invention can also minimize the trauma to the patient by making more precise ablations and minimizing unnecessary tissue destruction. Embodiments of the invention can use bipolar ablation which results in narrower lesions and less atrial debulking than traditional monopolar ablation approaches. Embodiments of the invention can also reduce the trauma on the patient by making the procedure achieve its objectives in a shorter time. This is done by allowing the surgeon to create linear lesions in the heart from the epicardial surface of the beating heart.

In some embodiments, a bipolar ablation device 30 in which a grounding electrode is in close proximity to a conductive tip) can create narrower and deeper lesions. The grounding electrode can be approximately the same dimension as the conductive tip, and both electrodes can be used to create the lesion.

Embodiments of the bipolar ablation device 30 can be designed to be used in a minimally-invasive environment (e.g., a mini-thoracotomy or an endoscopic procedure). The ablation device 30 can clamp atrial tissue in a two-step process in order to minimize the time of complete blood flow occlusion while ensuring a continuous lesion. Some embodiments of the invention can use magnets in order to latch two handle halves together in a secure and predetermined orientation. Other embodiments of the invention can use a single cable routed through two separate small jaws, looped around a larger jaw, and then locked to the larger jaw in order to actuate the smaller jaws individually. Once both jaws 24, 26 are appropriately positioned, they can be brought together at a hinge point and along an operating shaft to be assembled. Embodiments of the invention can use magnets, keys, accessory tools, and/or visualization techniques to quickly and securely assemble the pieces in a predetermined relation to each other. After assembly, the jaws 24, 26 may be opened and closed to act as a bipolar ablation device. Removal from the patient after ablation can be done as an assembled unit or after disassembly. In one embodiment, to align the jaws, magnets can be positioned in a hinge area. The operating shaft can be steerable to facilitate insertion and blunt dissection. An appropriate transmurality algorithm may be used to indicate a complete lesion to the surgeon or to terminate power when a lesion is completed. Some embodiments of the ablation device 30 can be inserted from a thorocotomy to simultaneously ablate all the pulmonary veins 12, or the access can be from another incision, such as sub-xyphoid incision. Alternatively, the pulmonary veins 12 may be isolated singularly, in pairs, or in any suitable combination.

The ablation device 30 can be designed to isolate the pulmonary veins 12 for ablating, in some embodiments, the left pulmonary veins 16 separately, from the right pulmonary veins 14. The ablation device 30 can include lower jaw assembly 32 and an upper jaw assembly 90. As shown in FIG. 3, the lower jaw assembly 32 can include an elongated arm 34 with a handle 36 on a proximal end 38 of the ablation device 30 and two separate pivoting jaws 42, 62 on the distal end 40 of the ablation device 30.

The arm 34 can include a spring-loaded proximal hinge 48 pivotally connecting a proximal jaw 42 to the handle 36. The proximal jaw 42 can include a proximal spring in the proximal hinge 48 for bearing against and maintaining the proximal jaw 42 in an open position. A proximal electrode 50 can be mounted on the proximal jaw 42 for transferring ablation energy to atrial tissue 10. As shown, in FIG. 3A, the proximal electrode 50 can include a cover 51 to prevent direct contact with the atrial tissue 10. A supply tube 52 can be in fluid communication with a chamber 58 formed by the cover 51. A proximal supply tube 74 can extend from the handle 36 to a fluid supply 122 (as shown in FIG. 6). A conductor 56 can be mounted on the arm 34 and connected to the proximal electrode 50. The conductor 56 can extend along the lower jaw assembly 32 and can, extend from the handle 36 to an ablation energy source 120 (as shown in FIG. 6).

As shown in FIG. 3, adjacent a distal end 40 of the lower jaw assembly 32, a distal jaw 62 can be connected to the arm 34 by a spring-loaded distal hinge 68 to maintain the distal jaw 62 in an open position. The distal jaw 62 can include a distal electrode 70 with a distal cover 72 surrounding the distal electrode 70 to form a chamber 73, as shown in FIG. 3B. A distal supply tube 74 can be positioned on the arm 34 and can be in fluid communication with the chamber 73. The distal supply tube 74 can extend along the lower jaw assembly 32 from the handle 36 to a fluid supply 122 (as shown in FIG. 6). A conductor 78 can be mounted on the arm 34 and can be connected to the distal electrode 70. The conductor 78 can extend along the lower jaw assembly 32 from the handle 36 to an ablation energy source 120 (as shown in FIG. 6).

As shown in FIG. 3, the handle 36 can include guides 82 and magnets 83 for assembly and alignment with the upper jaw assembly 90 (as shown in FIG. 4). A proximal jaw actuator 54 can be mounted on the proximal end 36 near the handle 36 and can be connected to the proximal jaw 42 through the proximal jaw hinge 48. The proximal jaw actuator 584 can bear against the spring-loaded proximal jaw hinge 48 to overcome the force holding the proximal jaw 42 in the open position and move the proximal electrode 50 into a tissue engagement position.

A distal jaw actuator 76 can be connected to the distal jaw 62 through the distal jaw hinge 68. The distal jaw actuator 76 can bear against the spring-loaded distal jaw hinge 68 to overcome the spring force and move the distal electrode 70 into a tissue engagement position. As shown in FIG. 3, the distal actuator 76 and the proximal actuator 54 can be connected to a cable loop 85, and can be actuation levers, in one embodiment. Both jaws 42, 62 can be spring-loaded in an open position. The jaws 42, 62 can include electrodes 50, 70. The distal and proximal actuators 54, 76 can be attached to a sliding block (not shown) that can slide parallel to the arm 34. One end of the cable 85 can be attached to the distal actuator 76. The cable 85 can extend along the length of the arm 34 and into the distal jaw 62. The cable 85 can form a loop outside the lower jaw assembly 32 and can then extend into the proximal jaw 42. The cable 85 can then extend back down the arm 34 and can attach to the proximal actuator 54. In other embodiments, the cable 85 can be actuated by a method other than a lever, such as thumb slide, a knob, etc.

After proper dissection, the lower jaw assembly 32 can be placed through an incision or port into the right side of the patient's chest. The lower jaw assembly 32 can be guided into the oblique sinus 18 (as shown in FIG. 2) until the electrodes 50, 70 are positioned around the pulmonary veins 12.

As shown in FIG. 4, the upper jaw assembly 90 can include a handle 92 and an upper arm 96. An upper electrode 98 can be mounted on the upper arm 96 at the distal end 40 of the ablation device 30. The upper arm 96 can be attached to the lower jaw assembly 32 by threading the upper electrode 98 and the adjacent portion of the upper arm 96 through the loop of the cable 85. The handle 92 can include receiving ports for the guides 82 (as shown in FIG. 3) on the handle 36 of the lower jaw assembly 32. A cable slot 97 can be positioned on the upper arm 96 adjacent the upper electrode 98. A conductor 95 can extend from the upper electrode 98 along the upper arm 96 through the handle 92 to the ablation energy source 120 (as shown in FIG. 6). When properly aligned, the handle 36 and the handle 92 can mate with each other, and the loop of the cable 85 can be secured around the upper arm 96 at the cable slot 97 to form an arm clamp 99.

As shown in FIG. 4A, the upper electrode 98 can include a cover 100 that can form a chamber 101. An upper supply tube 102 can be in fluid communication with the chamber 101. The upper supply tube 102 can extend through the upper arm 96 from the handle 92 to the liquid source 122 (as shown in FIG. 6).

The handles 36, 92 of the upper jaw assembly 32 and lower jaw assembly 90 can include one or more magnets 83 that can hold the handles 36, 92 together. The cable 85 can be attached to the arm clamp 99 at the distal end 40 and a clamp actuator 106 at the proximal end 38 of the ablation device 30. The upper electrode 98 can be a single long electrode approximately the same length as the sum of the lengths of the distal electrode 70 and proximal electrode 50. The upper electrode 98 can be aligned with the distal electrode 70 and proximal electrode 50 to form a single bipolar ablating device 108. In some embodiments, the bipolar ablating device 108 can perform ablations in three configurations—upper electrode 98 and distal electrode 70; upper electrode 98 and proximal electrode 50; or upper electrode 98, distal electrode 70, and proximal 50 electrode.

In one embodiment, a distal end of the proximal electrode 50 can be adjacent to a proximal end of the distal electrode 70 on the upper jaw assembly 32. The electrodes 50, 70, 98 can be formed in a particular shape with respect the geometries of the tissue being ablated. The patient's size and age can determine the shape of the electrodes 50, 70, 98.

As shown in FIG. 5, pulling back on the distal and proximal actuation levers 54, 76 together can tighten the loop of the cable 85 so that it can drop into the cable slot 97. Turning the clamp actuator 106 can lock the cable 85 to the upper jaw 94.

FIG. 6 is a bottom perspective view of the ablating device 30. The operation of the distal actuator 70 is shown pulling the distal electrode 70 toward the upper electrode 98 for clamping the atrial tissue 10 around the left pulmonary veins 16. The proximal jaw 42 can be positioned over the right pulmonary veins 14 allowing some blood flow through the pulmonary veins 12. A ratcheting mechanism 112 can be used to lock the distal actuator 76 in various positions to accommodate different tissue thickness. After ensuring proper placement, the distal electrode 70 can be actuated and the ablation can be performed. The ablating power supply 120 can be connected to the conductors 56, 78, 95 to provide independently controllable energy to each electrode 50, 70, 98, depending on when energization is needed to ablate the atrial tissue 10. The liquid source 122 can be in fluid communication with the chambers 58, 73, 101 of the electrodes 50, 70, 98. A saline liquid can be forced into the chambers 58, 73, 101 to flow through pores in the covers 51, 72, 100. The covers 51, 72, 100′ can be constructed of a porous polymer material from a supplier such as Porex Porous Products Group, 500 Bohannon Rd., Fairburn, Ga. 30213-2828. The liquid source 122 can pump a saline or other suitable liquid into the chambers 58, 73, 101 for conducting the ablation energy (such as radio frequency energy) through the covers 51, 72, 100 and into the atrial tissue 10 between the upper electrode 98 and one or both of the proximal electrode 50 and the distal electrode 70.

The proximal actuator 54 can also be rotated to pull the proximal electrode 50 toward the upper electrode 98 in a tissue engagement position that will completely occlude blood flow through the pulmonary veins 12. Use of the proximal electrode 50 can ensure alignment and continuity along the length of the lesion.

As quickly as possible to minimize the time of complete occlusion, a distal release button 80 (as shown in FIG. 6) can be actuated to allow the distal actuator 76 and the electrode 70 to be released and the spring-loaded hinge 68 to move the distal electrode 70 into an open position. The proximal electrode 50 can then be the only electrode in contact with the atrial tissue 10. After ensuring proper placement, the proximal electrode 50 can be activated and the ablation can be performed.

Once the ablation is complete, a proximal release button (not shown) can be actuated to release the proximal electrode 50 from its tissue engagement position and allow the spring-loaded hinge 48 to move the proximal electrode 50 into an open position. The clamp 99 can be released to unlock the cable 85 and allow the upper assembly 90 to be separated from the lower jaw assembly 32.

In operation, the lower jaw assembly 32 can be inserted into the patient through an incision to bring the proximal and distal electrodes 50, 70 into contact with the right and left pulmonary veins 14, 16. The upper jaw assembly 90 can be inserted through the incision or port and guided first through the loop of the cable 85, then through the transverse sinus until the magnets 83 on the handles 36, 92 line up with their corresponding guides 82.

The distal jaw 62 can be used to ablate the atrial tissue adjacent one pulmonary vein first. The tissue adjacent the pulmonary veins can be ablated by the distal electrode 70. To maintain the continuity of the lesion, the proximal jaw 42 can be moved to the closed position to facilitate alignment with the previous lesion and the distal jaw 62 can be released into the open position. The atrial tissue adjacent the other pulmonary veins can be ablated by energizing the proximal electrode 50.

FIG. 7 illustrates the proximal actuator 54 and the distal actuator 76 positioned to clamp both the proximal jaw 42 and the distal jaw 62 against atrial tissue 10 and/or the upper jaw 94. FIG. 8 illustrates the distal actuator 76 positioned to release the distal jaw 62 and the proximal actuator 54 positioned to clamp the proximal jaw 42.

As shown in FIG. 9, one embodiment of the ablation device can be a two-piece bipolar ablation device 130 with separable electrodes 148, 162. The two-piece ablation device 130 can use a two-step mechanical process to clamp the atrial tissue 10 around the pulmonary veins 14, 16. The two-piece ablation device 130 can be positioned to clamp around one set of pulmonary valves then the other. The compound ablation device 130 can allow some blood flow and can be used on a beating heart.

The ablation device 130 can include a lower jaw 154 and an upper jaw assembly 132 that can be independent and separable. Each jaw assembly 132, 154 can be individually manipulated into the appropriate space. Once positioned, the jaw assemblies 132, 154 can be brought together to create a bipolar system 140.

The upper jaw assembly 132 can include an upper arm 134 with an upper handle (not shown) on a proximal end 138 and an upper-jaw 142 on a distal end 140. A fixed upper jaw hinge 146 or use of a semi-flexible material that can be positioned on the upper arm 134 between the upper handle (not shown) and the upper jaw 142. An upper electrode 148 can be mounted on the upper jaw 142 at the distal end 140. The upper electrode 148 can include a cover (not shown) and a conductor (not shown). The conductor can be connected to the upper electrode 148 and can extend along the upper arm 134 from the upper handle (not shown) to an ablation energy source (not shown). The cover can be positioned over the upper electrode 148 to form a chamber (not shown). An upper supply tube can extend along the upper arm 134 from the handle (not shown) to a liquid source (not shown).

The lower jaw assembly 154 can include an arm 155 having a lower jaw 156 and a lower jaw hinge 160. A lower electrode 162 can be mounted on a distal end 163 of the lower jaw assembly 154. A cover can be positioned over the lower electrode 162 to form a chamber (not shown). A lower supply tube (not shown) can be connected to the chamber and can extend along the lower arm 155 from a lower handle 172 to a liquid source 5. A slider tube 135 can have a handle 136 that can be pushed toward the distal end 140. As the slider tube 135 passes over the upper jaw hinge 146 and lower jaw hinge 160 the upper electrode 148 and lower electrode 162 clamp together.

FIGS. 10, 10A, and 10B are additional perspective views of the ablation device 30 in various positions. FIG. 10 illustrates the proximal actuator 54 and the distal actuator 76 in first positions which cause the proximal jaw 42 and the distal jaw 62 to both be open. In FIG. 10, the cable 85 is loose within the arm clamp 99. FIG. 10A illustrates the distal actuator 76 in a second position in which the distal jaw 62 is clamped with respect to the upper jaw 94, the proximal actuator 54 remaining in the first position, and the cable 85 tightened within the arm clamp 99. FIG. 10B illustrates the distal actuator 76 back in the first position, the proximal actuator 54 in the second position in which the proximal jaw 42 is clamped with respect to the upper jaw 94, and the cable 85 tightened within the arm clamp 99.

FIG. 11 is a schematic illustration of the ablation device 30 within a patient's heart. The upper jaw 94 can be positioned above the superior left and right pulmonary veins 12. The distal jaw 62 can, be positioned through the oblique sinus 18 and below the inferior left and right pulmonary veins 12. The proximal jaw 42 can be positioned below the inferior right pulmonary veins 14. The arms 34 and 96 can extend out of an incision in the patient's side.

One embodiment of the invention produces linear radio frequency lesions in the atria using a hemostat device. However, embodiments of the invention can also be used with other energy sources, such as microwave energy, cryogenic energy, thermal energy, etc. Also, embodiments of the invention can be used for creating lesions in other tissues such as lung or liver resections. Additionally, embodiments of the invention can be implemented with various alignment techniques, such as parallel clamping and magnetically-aligned electrodes. The invention can provide a method and embodiments of an ablation device 30 for creating lesions. Such devices are especially useful for ablating on a beating heart, but can also be used on a stopped heart (i.e., during cardiopulmonary bypass).

Various additional features and advantages of the invention are set forth in the following claims. 

1.-15. (canceled)
 16. A method of ablating target tissue adjacent pulmonary veins of a patient, the method comprising: inserting a lower jaw assembly through an incision in the patient; inserting an upper jaw assembly through the incision; coupling the upper jaw assembly to the lower jaw assembly; moving at least one of a proximal actuator and a distal actuator in order to position at least one of a proximal jaw and a distal jaw with respect to an upper jaw; and providing ablation energy to at least one of an upper electrode, a proximal electrode, and a distal electrode.
 17. The method of claim 16 and further comprising providing ablation energy individually to at least one of an upper electrode, a proximal electrode, and a distal electrode.
 18. The method of claim 16 and further comprising providing a liquid to at least one of an upper electrode, a proximal electrode, and a distal electrode.
 19. The method of claim 16 and further comprising coupling the upper jaw assembly to the lower jaw assembly with at least one of a magnet and a cable.
 20. The method of claim 16 and further comprising moving at least one of the proximal actuator and the distal actuator perpendicular to an arm of at least one of the upper jaw assembly and the lower jaw assembly.
 21. The method of claim 16 and further comprising moving at least one of a trigger, a knob, and a lever to move at least one of the proximal actuator and the distal actuator.
 22. The method of claim 16 and further comprising moving a distal release button to release distal jaw after performing an ablation.
 23. The method of claim 16 and further comprising providing at least one of radio frequency energy, thermal energy, cryogenic energy, and microwave energy. 